This research is designed to define the effects of a maternal protein-deficient diet during gestation on hypothalamic, pituitary and thyroid function in the dam. It is also intended to elucidate the effects of maternal protein deprivation on morphogenesis of the fetal neonatal and postnatal hypothalamus and pituitary and the secretory activity of the hypothalamus, pituitary and thyroid. The effects of postnatal diet will also be examined. BIBLIOGRAPHIC REFERENCES: Shrader, R. E., Hastings-Roberts, M. M., Ferlatte, M. I. and Zeman, F. J. Effect of prenatal protein deprivation on fetal and neonatal thyroid morphology in the rat. J. Nutr. 107: 213-220 (1977). Shrader, R. E., Ferlatte, M. I., Hastings-Roberts, M. M., Schoenborne, B. M., Hoernicke, C. A., and Zeman, F. J. Thyroid function in prenatally protein-derived rats. J. Nutrition 107: 221-229 (1977).